Panic in tcp_input

Hi

I'm seeing this panic quite regularly now.  Most recent sighting on r251858.

cpuid = 15
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xffffff846b258130
vpanic() at vpanic+0x126/frame 0xffffff846b258170
panic() at panic+0x43/frame 0xffffff846b2581d0
__rw_assert() at __rw_assert+0x171/frame 0xffffff846b2581e0
vm_page_busy() at vm_page_busy+0x27/frame 0xffffff846b258200
vm_fault_hold() at vm_fault_hold+0x2ed/frame 0xffffff846b258450
vm_fault() at vm_fault+0x77/frame 0xffffff846b258490
trap_pfault() at trap_pfault+0x1b2/frame 0xffffff846b2584f0
trap() at trap+0x586/frame 0xffffff846b258650
calltrap() at calltrap+0x8/frame 0xffffff846b258650
--- trap 0xc, rip = 0xffffffff8054518e, rsp = 0xffffff846b258710, rbp = 0xffffff846b258810 ---
tcp_input() at tcp_input+0x12e/frame 0xffffff846b258810
ip_input() at ip_input+0xca/frame 0xffffff846b258860
netisr_dispatch_src() at netisr_dispatch_src+0x90/frame 0xffffff846b2588d0
ether_demux() at ether_demux+0x140/frame 0xffffff846b258900
ether_nh_input() at ether_nh_input+0x315/frame 0xffffff846b258930
netisr_dispatch_src() at netisr_dispatch_src+0x90/frame 0xffffff846b2589a0
ether_demux() at ether_demux+0xb2/frame 0xffffff846b2589d0
ether_nh_input() at ether_nh_input+0x315/frame 0xffffff846b258a00
netisr_dispatch_src() at netisr_dispatch_src+0x90/frame 0xffffff846b258a70
igb_rxeof() at igb_rxeof+0x507/frame 0xffffff846b258ae0
igb_msix_que() at igb_msix_que+0xf1/frame 0xffffff846b258b30
intr_event_execute_handlers() at intr_event_execute_handlers+0x90/frame 0xffffff846b258b70
ithread_loop() at ithread_loop+0x138/frame 0xffffff846b258bb0
fork_exit() at fork_exit+0x84/frame 0xffffff846b258bf0
fork_trampoline() at fork_trampoline+0xe/frame 0xffffff846b258bf0
--- trap 0, rip = 0, rsp = 0xffffff846b258cb0, rbp = 0 ---
Uptime: 9h1m32s
Dumping 1847 out of 16368 MB:..1%..11%..21%..31%..41%..51%..61%..71%..81%..91%

#0  doadump (textdump=1) at pcpu.h:236
236     pcpu.h: No such file or directory.
        in pcpu.h
(kgdb) #0  doadump (textdump=1) at pcpu.h:236
#1  0xffffffff8044d327 in kern_reboot (howto=260)
    at /usr/src/sys/kern/kern_shutdown.c:447
#2  0xffffffff8044d835 in vpanic (fmt=<value optimized out>, 
    ap=<value optimized out>) at /usr/src/sys/kern/kern_shutdown.c:754
#3  0xffffffff8044d883 in panic (fmt=<value optimized out>)
    at /usr/src/sys/kern/kern_shutdown.c:683
#4  0xffffffff8044b701 in __rw_assert (c=<value optimized out>, 
    what=<value optimized out>, file=<value optimized out>, 
    line=<value optimized out>) at /usr/src/sys/kern/kern_rwlock.c:1147
#5  0xffffffff805e1507 in vm_page_busy (m=0xfffffe0425a83c08)
    at /usr/src/sys/vm/vm_page.c:476
#6  0xffffffff805cfb1d in vm_fault_hold (map=0xfffffe0001000000, 
    vaddr=18446743524069429248, fault_type=7 '\a', fault_flags=0, m_hold=0x0)
    at /usr/src/sys/vm/vm_fault.c:400
#7  0xffffffff805cf7e7 in vm_fault (map=0xfffffe0001000000, 
    vaddr=<value optimized out>, fault_type=2 '\002', fault_flags=0)
    at /usr/src/sys/vm/vm_fault.c:224
#8  0xffffffff8060cfd2 in trap_pfault (frame=0xffffff846b258660, usermode=0)
    at /usr/src/sys/amd64/amd64/trap.c:767
#9  0xffffffff8060c866 in trap (frame=0xffffff846b258660)
    at /usr/src/sys/amd64/amd64/trap.c:463
#10 0xffffffff805f58b3 in calltrap ()
    at /usr/src/sys/amd64/amd64/exception.S:228
#11 0xffffffff8054518e in tcp_input (m=<value optimized out>, off0=Cannot access memory at address 0x14
)
    at counter.h:45
#12 0xffffffff8053d61a in ip_input (m=0xfffffe0104bf0400)
    at /usr/src/sys/netinet/ip_input.c:808
#13 0xffffffff8051cf30 in netisr_dispatch_src (proto=<value optimized out>, 
    source=<value optimized out>, m=0xfffffe0104bf0400)
    at /usr/src/sys/net/netisr.c:1013
#14 0xffffffff805123d0 in ether_demux (ifp=<value optimized out>, 
    m=0xfffffe0104bf0400) at /usr/src/sys/net/if_ethersubr.c:849
#15 0xffffffff805130f5 in ether_nh_input (m=<value optimized out>)
    at /usr/src/sys/net/if_ethersubr.c:644
#16 0xffffffff8051cf30 in netisr_dispatch_src (proto=<value optimized out>, 
    source=<value optimized out>, m=0xfffffe0104bf0400)
    at /usr/src/sys/net/netisr.c:1013
#17 0xffffffff80512342 in ether_demux (ifp=0xfffffe0035689000, 
    m=0xfffffe0104bf0400) at /usr/src/sys/net/if_ethersubr.c:758
#18 0xffffffff805130f5 in ether_nh_input (m=<value optimized out>)
    at /usr/src/sys/net/if_ethersubr.c:644
#19 0xffffffff8051cf30 in netisr_dispatch_src (proto=<value optimized out>, 
    source=<value optimized out>, m=0xfffffe0104bf0400)
    at /usr/src/sys/net/netisr.c:1013
#20 0xffffffff803055a7 in igb_rxeof (count=1499)
    at /usr/src/sys/dev/e1000/if_igb.c:4723
#21 0xffffffff80305aa1 in igb_msix_que (arg=0xfffffe002c1ceb38)
    at /usr/src/sys/dev/e1000/if_igb.c:1590
#22 0xffffffff80422d90 in intr_event_execute_handlers (
    p=<value optimized out>, ie=0xfffffe002e008200)
    at /usr/src/sys/kern/kern_intr.c:1263
#23 0xffffffff804237f8 in ithread_loop (arg=0xfffffe002e0431a0)
    at /usr/src/sys/kern/kern_intr.c:1276
#24 0xffffffff80420814 in fork_exit (
    callout=0xffffffff804236c0 <ithread_loop>, arg=0xfffffe002e0431a0, 
    frame=0xffffff846b258c00) at /usr/src/sys/kern/kern_fork.c:991
#25 0xffffffff805f5d7e in fork_trampoline ()
    at /usr/src/sys/amd64/amd64/exception.S:602
#26 0x0000000000000000 in ?? ()
Current language:  auto; currently minimal
(kgdb) 

-- 
Ian Freislich